7 ideas
21566 | 'Propositional functions' are ambiguous until the variable is given a value [Russell] |
17743 | De Morgan introduced a 'universe of discourse', to replace Boole's universe of 'all things' [De Morgan, by Walicki] |
21567 | 'All judgements made by Epimenedes are true' needs the judgements to be of the same type [Russell] |
23457 | Type theory cannot identify features across levels (because such predicates break the rules) [Morris,M on Russell] |
21556 | Classes are defined by propositional functions, and functions are typed, with an axiom of reducibility [Russell, by Lackey] |
21568 | A one-variable function is only 'predicative' if it is one order above its arguments [Russell] |
21342 | A relation is internal if two things possessing the relation could not fail to be related [Moore,GE, by Heil] |